Heriberto Bitencourt | UFPA - Federal University of Pará (original) (raw)

Papers by Heriberto Bitencourt

Journal of Molecular Structure, Dec 1, 2021

Abstract For the first time, it is performed a discussion on the structure, reactivity, and nonli... more Abstract For the first time, it is performed a discussion on the structure, reactivity, and nonlinear optical (NLO) response of new metabolites dihydrochalcone (4), 3,4,5-trimethoxychalcone (5), and 2,3,4,4’-tetramethoxydihydrochalcone (6) obtained by biotransformation of chalcone (1), 3,4,5-trimethoxychalcone (2), and 2,3,4,4’-tetramethoxychalcone (3) using Aspergillus flavus, an endophytic fungus naturally present in the Amazon Biome. Density Functional Theory methods associated with the 6–311++G(d,p) basis set and the Polarizable Continuum Model ensure either solvent contributions, as well as relevant quantum mechanical effects such as long-range and dispersion interactions. Usually, due to the environmental polarizability and the strong polar character inherent to the trans-isomer, such structure is dominating concerning the cis one. However, the vibrational analysis indicates that cis conformer prevails in 1, but the systematic inclusion of methoxy groups is the stabilizer factor for the trans structure in the chromophores 2 and 3. Moreover, the results also indicate that minimal structural changes have a severe impact on the electronic structure of the material. Essentially, the metabolic reaction substitutes alkene bonds in chalcones (1–3) by alkane bridges in dihydrochalcones (4–6), causing a strong hypsochromism (ca. 70 nm) in the UV–vis spectra and a reduction of the electrophilic power of the chromophores. Nevertheless, the inclusion of electron donor groups reverses this behavior and enhances the NLO response of the metabolites. In particular, the biotransformed chromophores can present static first-hyperpolarizability varying from 6.37 × 10 − 30 to 59.35 × 10 − 30 esu, which can be one hundred and sixty times greater than that reported for urea, a standard NLO material with β total = 0.37 × 10 − 30 esu. All chromophores are classified as moderate nucleophiles ( 2.0 ≤ N ≤ 3.0 eV) and strong electrophiles ( ω > 1.5 eV). These results suggest that the biosynthesized chromophores have great reactivity, besides being promissory for optoelectronic and photonic applications.

Experimental Parasitology, 2016

Maring a, Paran a, Brazil h i g h l i g h t s g r a p h i c a l a b s t r a c t Chalcones 1e3 ind... more Maring a, Paran a, Brazil h i g h l i g h t s g r a p h i c a l a b s t r a c t Chalcones 1e3 induced mitochondrial changes in promastigotes of L. (V.) braziliensis. Synthetic chalcones 1e3 induced rounded shape in L. (V.) braziliensis. Chalcones 1e3 showed cytoplasmic and nuclear shrinkage in L. (V.) braziliensis. Chalcones 1e3 exhibited nucleosome-sized DNA fragments in L. (V.) braziliensis. Chalcones induced changes in promastigotes suggesting apoptosis-like cell death.

Journal of Biophysical Chemistry, 2023

N-11-azaartemisinins potentially active against Plasmodium falciparum are designed by combining m... more N-11-azaartemisinins potentially active against Plasmodium falciparum are designed by combining molecular electrostatic potential (MEP), ligand-receptor interaction, and models built with supervised machine learning methods (PCA, HCA, KNN, SIMCA, and SDA). The optimization of molecular structures was performed using the B3LYP/6-31G* approach. MEP maps and ligand-receptor interactions were used to investigate key structural features required for biological activities and likely interactions between N-11-azaartemisinins and heme, respectively. The supervised machine learning methods allowed the separation of the investigated compounds into two classes: cha and cla, with the properties ε LUMO+1 (one level above lowest unoccupied molecular orbital energy), d(C 6-C 5) (distance between C 6 and C 5 atoms in ligands), and TSA (total surface area) responsible for the classification. The insights extracted from the investigation developed and the chemical intuition enabled the design of sixteen new N-11-azaartemisinins (prediction set), moreover, models built with supervised machine learning methods were applied to this prediction set. The result of this application showed twelve new promising N-11

Research, Society and Development, Oct 16, 2022

As principais atividades de curcuminóides: uma revisão The main activities of curcuminoids: a rev... more As principais atividades de curcuminóides: uma revisão The main activities of curcuminoids: a review Las principales actividades de los curcuminoides: una revisión

Brazilian Journal of Development, Nov 19, 2021

As instituições de ensino tiveram que se adaptar a uma nova modalidade de ensino, o remoto/virtua... more As instituições de ensino tiveram que se adaptar a uma nova modalidade de ensino, o remoto/virtual. Devido ao distanciamento social ficou impossível o contato presencial de alunos e professores, com o impacto dessa mudança emergencial alunos e professores vêm enfrentando dificuldades na aprendizagem remota quanto ao uso das ferramentas digitais que facilitem o ensino. O presente trabalho de conclusão de curso, foi realizado no primeiro semestre de 2021 nos meses de abril até a primeira quinzena de maio, o público alvo foram 15 estudantes da turma da 2ª etapa da modalidade (EJA) Educação de Jovens e Adultos e 1 docente da rede pública estadual de São Sebastião da Boa Vista-PA. Tratou-se de uma pesquisa quali-quantitativa, de natureza aplicada com o estudo de caso. Como instrumento de coletas de dados, utilizaram-se questionários disponibilizados via Whatsapp e impresso. Os resultados mostraram que a maioria dos alunos sente dificuldade quanto ao ensino de Química, além disso, alguns não dispõem de recursos tecnológicos sendo necessário ir à escola para ter acesso ao material didático e tirar dúvidas relacionada a disciplina, também, expuseram o desejo de utilizar os recursos digitais na aprendizagem durante esse período remoto. Já o professor da disciplina em questão, relatou que sente dificuldades quanto ao uso das tecnologias e que gostaria que a escola disponibilizasse cursos de capacitação para melhor atender seu alunado. A partir da análise dos resultados ficou visível a preocupação quanto ao processo de ensino aprendizagem de Química em turma da EJA. A pesquisa traz em seu encarte a possibilidade de aproximar o aluno da disciplina Química e apresentar estratégias que mitiguem essas dificuldades, mostrando a importância de aprender Química para adquirir uma aprendizagem eficaz.

Research, Society and Development, Dec 13, 2021

Síntese e avaliação biológica de chalconas e derivados in vitro contra célula AGP01 Synthesis and... more Síntese e avaliação biológica de chalconas e derivados in vitro contra célula AGP01 Synthesis and biological evaluation of chalcones and derivatives in vitro against AGP01 cell Síntesis y evaluación biológica de chalconas y derivados in vitro frente a células AGP01

Computational chemistry, 2023

Artemisinins tested against W-2 strains of malaria falciparum are investigated with molecular ele... more Artemisinins tested against W-2 strains of malaria falciparum are investigated with molecular electrostatic potential (MEP), in an attempt to identify key features of the compounds that are necessary for their activities, as well as to investigate likely interactions with the receptor in a biological process and to use that information to propose new molecules. In order to discover the best geometry involving the ligand-receptor complexes (heme) studied and help in the proposition of the new derivatives, molecular simulations of interactions between the most negative charged region around the peroxide and heme locates (the ones around the Fe 2+ ion) were carried out. In addition, PCA (principal components analysis), HCA (hierarchical cluster analysis), SDA (stepwise discriminant analysis), and KNN (K-nearest neighbor) multivariate models were employed to investigate which descriptors are responsible for the classification between the higher and lower antimalarial activity of the compounds, and also this information was used to propose new potentially active molecules. The information accumulated in studies of MEP, molecular docking, and multivariate analysis supported the proposal of new structures with potential antimalarial activities.

Journal of Engineering Research, Dec 6, 2022

All content in this magazine is licensed under a Creative Commons Attribution License. Attributio... more All content in this magazine is licensed under a Creative Commons Attribution License. Attribution-Non-Commercial-Non-Derivatives 4.0 International (CC BY-NC-ND 4.0).

Research, Society and Development, Jun 21, 2022

Estudo químico e atividade antibacteriana do extrato hidrometanólico do fungo de solo Thichoderma... more Estudo químico e atividade antibacteriana do extrato hidrometanólico do fungo de solo Thichoderma sp FSF12 Chemical study and antibacterial activity of the hydromethanolic extract of soil fungus Thichoderma sp FSF12 Estudio químico y actividad antibacteriana del extracto hidrometanólico del hongo del suelo Thichoderma sp FSF12

Brazilian Journals Editora eBooks, Nov 18, 2021

O conteúdo dos livros e seus dados em sua forma, correção e confiabilidade são de responsabilidad... more O conteúdo dos livros e seus dados em sua forma, correção e confiabilidade são de responsabilidade exclusiva dos autores. Permitido o download da obra e o compartilhamento desde que sejam atribuídos créditos aos autores, mas sem a

Planta Daninha, Dec 1, 2007

Atividade alelopática de chalcona sintética, de seus ...

Brazilian Journal of Development, Sep 21, 2021

In view of the current scene of Brazilian education, with the emergence of the Covid-19 pandemic,... more In view of the current scene of Brazilian education, with the emergence of the Covid-19 pandemic, the intrinsic primordiality of na interaction between distance student and teacher is observed. Thereat, educational institutions needed to adapt to a new way of teaching, in order to comply with the prevention and biosafety measures propagated by the World Healthy Organization (WHO), which the most important one is the social distance. The main way used to seek adaptation to the new education system was the use of Information and Communication Technologies (ICTs), especially in teaching Chemistry, furthermore, since before the current situation of Brazilian education, it is known that teachers had great difficulties in inserting alternative methods that used technology to facilitate the teaching-learning process, in many cases they are not familiar with this technology and because they believe that the dinamism of technological resources are very complex, therewith, seek the traditional teaching method as a comfort zone in an enviroment already explored and known. In this context, the emergence of new educational instruments has become essential to awaken the interest of students in these difficult times. In this way, the presente work aims, through a bibliographical review, to explore some tools that make the teaching of Chemistry more interesting and viable for students, even if it is far from the classroom, in addition to demonstrating activities where such tools can be used.

IntechOpen eBooks, Jul 15, 2020

In this chapter, firstly, we briefly review aspects of the approximation of quantum chemistry, mo... more In this chapter, firstly, we briefly review aspects of the approximation of quantum chemistry, molecular electrostatic potential (MEP), and chemometrics techniques, which are accredited as important tools in the development of chemical science and are frequently used in the study and design of bioactive compounds. Ultimately, we use MEP and pattern recognition (PR) techniques as tools to design nitrofuran compounds with biological activity against Trypanosoma cruzi (T. cruzi). PR models (PCA, HCA, KNN, SDA, and SIMCA) were constructed and demonstrated that 23 nitrofurans can be classified into two classes or groups: more active and less active according to their degrees of activity against T. cruzi. Properties such as charge on the N atom of the nitro group (QN1); the difference between the highest occupied molecular orbital (HOMO) energy and the lowest unoccupied molecular orbital (LUMO) energy (GAP energy); molecular representation of structure based on electron diffraction code of signal 5, unweighted (Mor05u); and Moriguchi water-octanol partition coefficient (MlogP) are responsible for the classification into more active and less active studied nitrofurans. It is interesting to notice that these properties represent three distinct classes of interactions between the nitrofurans and the biological receptor: electronic (QN1 and GAP energy), steric (Mor05u), and hydrophobic (MlogP). The results of the application of PR models on the validation set evidenced two nitrofuran compounds (compounds 25 and 30) as more promising for synthesis and biological assays, which in the future can be used to validate our PR models.

Research, Society and Development, Sep 19, 2021

Molecular electrostatic potential and pattern recognition models to design potentially active pen... more Molecular electrostatic potential and pattern recognition models to design potentially active pentamidine derivatives against Trypanosoma brucei rhodesiense Potencial eletrostático molecular e modelos de reconhecimento de padrões para desenhar derivados da pentamidina potencialmente ativos contra Trypanosoma brucei rhodesiense Potencial electrostático molecular y modelos de reconocimiento de patrones para diseñar derivados de pentamidina potencialmente activos contra Trypanosoma brucei rhodesiense

Journal of the Brazilian Chemical Society, Jul 1, 2011

O fungo Aspergillus flavus isolado como endofítico da planta Paspalum maritimum Trin. foi avaliad... more O fungo Aspergillus flavus isolado como endofítico da planta Paspalum maritimum Trin. foi avaliado quanto ao seu potencial de aplicação em reações de biotransformações. Os compostos chalcona (1), 3,4,5-trimetoxichalcona (2) e 2,3,4,4'-tetrametoxichalcona (3) foram biotransformados, respectivamente, na diidrochalcona (4), 3,4,5-trimetoxidiidrochalcona (5) e 2,3,4,4'-tetrametoxidiidrochalcona (6). As estruturas destes compostos foram determinadas por análises de RMN uni e bidimensionais e por espectrometria de massas. As diidrochalconas 5 e 6 são substâncias inéditas. The fungus Aspergillus flavus isolated as endophytic of the plant Paspalum maritimum Trin. was evaluated for its potential application in biotransformation reactions. The compounds chalcone (1), 3,4,5-trimethoxychalcone (2) and 2,3,4,4'-tetramethoxychalcone (3) were biotransformed, respectively, in dihydrochalcone (4), 3,4,5-trimethoxydihydrochalcone (5) and 2,3,4,4'-tetramethoxydihydrochalcone (6). The structures were elucidated by spectroscopic methods including 1D and 2D NMR techniques, and MS analysis. The dihydrochalcones 5 and 6 are new compounds.

Brazilian Journals Editora eBooks, Apr 29, 2022